The present invention relates to a motor-operated hand band grinder with a side abutment.
The publication xe2x80x9cBosch-Heimwerkerprogramm, Katalog, 1999/2000xe2x80x9d, page 88, discloses a hand band grinder with an abutment part, having a plane which can be arranged perpendicular to a grinding plane of the hand band grinder. During grinding with this hand band grinder, it is practically not possible to recognize an edge of the grinding band. Thereby the treated grinding surface of a workpiece can not be observed. A control of the work is therefore possible very poorly.
A further disadvantage of the above mentioned hand band grinder is that the abutment has a very small length normal to the grinding plane. Thereby the grinding on vertical edges is uncomfortable, since by the weight of the hand band grinder and a very short lever for the machine user, a very high support force must be brought to guide the band perpendicular to a workpiece surface, on which the abutment is laid. This high supporting force leads to high friction forces between the abutment and the workpiece surface. The hand band grinder is thereby guided along only with a significant force application to the grinding surface. This high force application leads under certain conditions to an undesirably high material removal.
Moreover, the abutment is not provided for a mobile use, but instead for a stationary utilization and thereby is less comfortable. Furthermore, the above mentioned abutment has no connection to a suction device, so that the grinding dust can be removed only by a machine-side suction device at the hand band grinder.
Accordingly, it is an object of the present invention to provide a hand band grinder which avoids the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of present invention resides, briefly stated, in a hand band grinder in which the plate part has a window-shaped opening over an edge of the grinding band and forms a guiding handle.
When the hand band grinder is designed in accordance with the present invention, the user can see an edge of the grinding band through the window-shaped opening. With an arcuate design of the plate part, additionally to the openings, a torsion-resistant connection of the plate part to a folding part of the abutment is obtained.
The arcuate plate part can be formed as a semi-ring. It has a central point located in the region of the grinding plane. Thereby a good operational property for the user are provided, since the plate part has a handle projecting substantially uniformly to the grinding plane, regardless of what position the hand band grinder together with the abutment part assumes to the workpiece.
In accordance with an advantageous embodiment of the present invention, the plate part is formed so that its abutment region is engageable by the hand of the user.
Another advantage of the invention is provided when the greatest distance of the plate part from the grinding plate is such as the distance of the handle of the hand band grinder from the grinding plate. This has the advantage that thereby a longer lever is formed during support of the user on the arcuate plate part and a specially high supporting moment is produced. The hand band grinder can be held with low supporting force on the grinding edge to be treated. The body of the user is therefore unloaded and he can concentrate on the grinding process.
For providing a reliable connection between the abutment part and the hand band grinder, it is advantageous when in accordance with the present invention a mounting is performed by at least one mounting part. For mounting the abutment part on the hand a grinder it is especially advantageous when the already available receptacle for a stationary device can be used for the mounting.
An especially efficient suction of the grinding dust is performed when in accordance with the present invention the abutment part at the location where the grinding band again enters in the machine has a dust throughgoing opening with a connection to a suction device.
In order to provide a fine treatment of the workpiece, it is advantageous when in accordance with the present invention the side of the plate part which faces the workpiece has a workpiece-refining coating which advantageously can be additionally dismountable.
It is also advantageous when in accordance with the present invention the plate part of the abutment is adjustable turnably to the grinding plane. Thereby different micro-grinding angles can be adjusted between the surface to be ground and the workpiece surface on which the abutment part is guided.
The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.